Changing the mandrel of a tubeextrusion press



Nov. 17, 1964 F. MAASS ETAL 3,157,283

CHANGING THE MANDREL OF A TUBE-EXTRUSION PRESS Filed Nov. 15, 1961 s Sheets-Sheet 1 Nov. 17, 1964 F. MAASS ETAL CHANGING THE MANDREL OF A TUBE-EXTRUSION PRESS Filed NOV. 13, 1961 3 Sheets-Sheet 2 Nov. 17, 1964 ss ETAL 3,157,283

CHANGING THE MANDREL OF A TUBE-EXTRUSION PRESS 5 Sheets-Sheet 3 Filed Nov. 13, 1961 figs e- United States Patent ch 1 Claim. (Cl. 207-19) It is known that the quality and the accuracy to gauge of tubes manufactured in a tube-extrusion press are primarily dependent upon the quality or condition of the mandrels, which have to be either cooled or preheated, and also tested for accuracy to gauge, and satisfactorily lubricated. This treatment of the mandrels is effected between two operations of the press, with the mandrel mounted therein. Now with high-speed presses it is impossible, in the short time available, even by applying internal and external cooling, to keep the mandrels always at the most advantageous temperature, so that they comparatively soon become useless, owing to the high heating, particularly in the case of the extrusion of steel.

Whilst eiforts have hitherto been made to effect the treatment of the mandrels fitted into the press as rapidly as possible by means of cooling or heating apparatus and lubricating appliances of various kinds, this invention entirely renounces such appliances arranged in the press, and accomplishes the treatment of the mandrels outside the press. For putting in and taking out the mandrels it employs a very rapidly acting appliance, which comprises a controlling device that actuates some or all of the putting-in and taking-out means in dependence upon the Working stroke of the press, for instance after the completion of such extrusion operation; the actuating of the means preferably being effected in dependence upon the return movement of the mandrel.

The invention further consists in an inserting and removing appliance which is suitable for controlling in the abovementioned sense, but which can also be successfully utilized independently of any controlling apparatus, for instance in the case of manual control, for the quick insertion and removal of mandrels. This apparatus is characterised by the feature that a wrench, which can travel to the mandrel mounting, is rotatably mounted on an arm which has a driving appliance for rotating the wrench, and that a clamping gripper that can be advanced to the mandrel is mounted on an arm movable in the direction of the mandrel and carrying an actuating appliance for the gripper. These two arms may be located parallel to one another, or may even be identical.

Further details of the invention can be gathered from the following description of a constructional example, and from the accompanyingdrawings, in which,

FIGURE 1 shows the lower portion of an upright extrusion press, partly in section, with a mandrel-changing appliance according to the invention in elevation;

FIGURE 2 a section on IIII in FIGURE 1;

FIGURE 3 a portion of FIGURE 1 on a larger scale;

FIGURE 4 a plan looking in the direction IV-IV in FIGURE 3; and

FIGURE 5 a plan looking in the direction V-V in FIGURE 3.

The platen 1 of the press slides in a frame 2;, and the container 3 is supported against the die 4, mounted in the frame 2. The platen 1 carries the press ram 5, in which slides the mandrel-holder 6, connected by means of a mounting sleeve 7 with the mandrel 8. The mounting sleeve 7 has fiat surfaces adapted to be engaged by a wrench. The mandrel-removing appliance 25 and the mandrel-inserting appliance 26 are each held at the side of the press by a bracket 9 on the frame 2, and each 3,157,283 Patented Nov. 17, 1964 comprises a guiding piece 10 which can be raised and lowered, and which carries a slideway 10a and a radially displaceable arm 11 slidable thereon. For the raising and lowering of the mandrel, each of the guiding pieces 10 is equipped with a cylinder 12 with a double-acting piston, and, for the forward and rearward movement of each of the arms 11, a cylinder 13 having a double-acting piston slidable therein is provided. The arms 11 each carry a rotatable wrench 14 for actuating the mounting sleeve 7. The wrenches are each rotated by a doubleacting piston, slidable in a cylinder 15. Each of the arms 11 also carries a gripper 17, with clamping jaws 16, for holding fast the mandrel 8. The clamping jaws of each gripper are actuated by means of a double-acting piston sliding in a cylinder 18.

For taking over removed mandrels 8 from the removing appliance 25, and for delivering mandrels 8 to be inserted to the inserting appliance 26, rotatable mandrel-carriers 19 and 19a respectively are provided, each with two or more U-shaped receivers, which can be used, either directly or with the aid of an interposed connecting and transporting means, for the transport of the mandrels from the removing appliance 25, past an inspection and treatment station 20, to the inserting appliance 26. The path of the mandrels is indicated by a dot-and-dash line 21, provided with arrows, in FIGURE 2.

The removing and inserting appliances may be controlled individually by hand or automatically by a general controlling apparatus, which executes a number of operations simultaneously or successively. The automatic controlling apparatus is here so designed that the change of mandrel is effected in the working cycle of the press. According to the adjustment of the controlling apparatus, the mandrel is changed either after each extrusion or after every second or third or subsequent extrusion. The control may for instance be released by every return stroke of the mandrel, or only by every second or third return stroke of the mandrel, and then effects in succession the action of the individual appliances for releasing the mandrel, for withdrawing the mandrel, for feeding and inserting a fresh mandrel, and for tightening the mandrel mounting. Such controlling appliances, operated electrically or hydraulically or mechanically, are generally known, and can be installed by any control technologist.

For de-mounting a mandrel, the wrench 14 and the gripper 16 of the removing appliance 25 are moved to the axis of the press, and, by an upward movement of the arm 11, are so raised that the wrench 14- slips into engagement with flats on the mounting sleeve 7 of the mandrelholder 8 (FIGURE 3), which may, for instance, hold the mandrel by means of a bayonet joint. Thereupon, in succession, the clamping jaws 16 are clamped for holding the mandrel, the mandrel is released from the mounting sleeve 7 by means of the wrench 14, the removing appliance 25, with the removed mandrel 8, is lowered and moved outwards, until the mandrel enters one of the U-shaped receivers of the mandrel-carrier 19, whereupon the clamping jaws are released, and the mandrel is held in the mandrel-carrier by known mechanical or magnetic means, while the mandrel-carrier turns round, so as to bring the mandrel into a position from which it can be removed to the inspection and treatment station 20 by known means not forming part of the present invention, and therefore not further described here. Similar known means carry a fresh mandrel from the station 20 to one of the U-shaped receivers of the mandrel-carrier 19a, which then revolves until the mandrel reaches the axis of the inserting appliance 26, whereupon the mandrel is engaged by the jaws 16, and the displaceable arm 11 is slid radially inwards thereby taking the mandrel out of the mandrel-carrier and bringing it into alinement with the axis of the mandrel-holder 6. By raising the inserting appliance this mandrel is pushed into the mounting sleeve 7. After actuation of the wrench for the arresting of the mounting sleeve, the clamping jaws 16 are released and the inserting appliance is lowered and moved outwards, so that the next mandrel can be taken by the mandrel-carrier. The operations of the removing and inserting appliances may be so arranged that the inserting appliance travels to the axis of the press with a fresh mandrel immediately after the removal of the used mandrel, so that the shortest possible changing time is attained.

Deviations from the constructional example described are obviously possible. The two wrenches 14 and the two grippers 17 may in some cases be jointly arranged upon a single longitudinally slidable arm. Instead of longitudinally slidable arms, it is also possible to employ rockable arms.

With slowly working presses, or those that need a change of mandrels only at relatively long intervals of time, the change of mandrel may be effected by means of a single longitudinally slidable or rockable arm which can be raised and lowered, with a wrench and clamping jaws mounted thereon.

What we claim is:

Mandrel-changing means for an extrusion press, comprising: a press ram, a mandrel-holder and a mandrel extending through the press ram, a mounting sleeve within the press ram connecting the lower end of the mandrelholder with the mandrel, two arms, each movable towards and away from the axis of the press ram, one of these arms serving as a mandrel-removing appliance and the other as a mandrel-inserting appliance, actuating means for moving the arms, a controllable clamping gripper mounted on each of the arms, each of these gripper being capable of holding the mandrel fast, actuating means for the grippers, a rotatable wrench mounted on each of the arms, means for rotating each wrench about the axis of the mandrel, and means for raising and lowering each wrench into and out of engagement with the mounting sleeve, the wrench on the mandrel-removing appliance being adapted, by rotating the mounting sleeve, to release the mandrel from the mandrel-holder while the clamping gripper on the same appliance holds the mandrel fast, and the wrench on the mandrel-inserting appliance being adapted, by rotating the mounting sleeve, to lock the mandrel to the mandrel-holder while the mandrel is still held fast by the clamping gripper on the said mandrelinserting appliance.

References Cited in the file of this patent UNITED STATES PATENTS 1,401,405 Hale Dec. 27, 1921 1,736,009 Nixon Nov. 19, 1929 1,884,874 Ross Oct. 25, 1932 2,264,012 Wasson Nov. 25, 1941 2,901,927 Morgan Sept. 1, 1959 2,929,499 Turner Mar. 22, 1960 2,976,943 Curtis Mar. 28, 1961 FOREIGN PATENTS 1,054,945 Germany Apr. 16, 1959 

